It would be nice to have to have the ability to plan are more specific route for a unit such that it passes through selected "way point" regions.
The "way point" regions could be selected by holding down ctrl + right click on the region. (sounds so easy if one does not have to implement it ^^)

There are many good reasons for not wanting to run the fastest route from A to B selected by the games pathfinding ;)

• Planning a pearl picking route
• Avoiding ice because summer might come up any time.
• Avoid detection by another player.
• and so on...
  

Just need option that unit can collect pearls automatically when map is open. It is tedious to collect a lot of pearls manually

Sure for the sake of collecting pearls automation certainly would be nice, and this excellent suggestion has been made in another thread. So make your support for that suggestion known there if you don't already have ;)

But this suggestion is more about being able to plot a more specific route for a unit in general, such that one does not have to babysit it every step of the way.